The field of the invention is nozzles capable of operating at high temperatures for the spraying of viscous liquids. The invention more particularly relates to nozzles useful at the tip of a sulphur gun of the type utilized to burn sulphur to manufacture sulphuric acid.
Sulphuric acid is typically made by pumping and burning molten sulphur in a brick lined furnace. In order to insure a complete combustion of the sulphur, the sulphur must be broken into a fine spray which essentially atomizes or vaporizes the sulphur in the sulphur furnace. If the sulphur is not sufficiently atomized it will not be completely burned and will be likely to contact the wall of the furnace or the boiler tubes therein thereby degrading the furnace wall and corroding the tubes in addition to affecting very seriously the boiler efficiency.
There has been a trend in sulphuric acid plants to increase the size of the sulphur burner to enable economic operation. Therefore there is a need for a high volume sulphur gun capable of use by even the largest plants. Production from a typical large volume plant is about one thousand eight hundred (1800) tons per day. Because of the large volume operation of most newer sulphur acid plants, these plants operate with furnaces having three separate sulphur guns to provide the necessary production volume. The use of multiple guns permits the operation of the plant at several production volumes and if the need for sulphuric acid decreases, one or more of the guns may be shut down. This avoids the expense of intermittent operation of the plant but even so, it is more costly, starting with the initial design of the plant, right down to normal maintenance after it is under normal operation, because design, construction, operation and maintenance have to be provided for three pieces of equipment instead of for only one.
Presently used sulphur guns are exposed to the high temperature of the burning sulphur which results in a degradation of the nozzle, often resulting in a stripping of the threads of the gun or nozzle, or both. The heat within the furnace often exceeds two thousand degrees (2000.degree.) Fahrenheit. When the furnace is first shut down the nozzle is not cooled by the sulphur passing through it and therefore the nozzle reaches a high temperature and present nozzles are not able to withstand such temperatures for any extended period of time.